The present invention relates to a method, and apparatus, for controlling the behavior of cars, and a traffic control system using the control method. In particular, the present invention relates to means for controlling car groups or the overall traffic flow including the car groups.
As a conventional technique for controlling cars traveling on a road by taking the efficiency, safety and environment into consideration, there is a traffic control system for controlling signals described in xe2x80x9cTraffic Engineering,xe2x80x9d edited and written by Iida, published by Kokumin Kagaku Sha in 1992, pp. 245-256.
In that system, complicated cars are separated as far as possible and signal waiting is reduced by controlling indications of signals and control parameters (cycle length, split, and offset). Especially, in system control for controlling timing of a plurality of signal groups disposed along a route, signal offset is determined by suitably designing a time width (through band) during which a traveling car can pass continuously without being stopped by a red light, as shown in FIG. 2.
As a different conventional technique for controlling traveling cars, there is an automatic driving control technique for suitably controlling the car speed and so on, on the basis of communication information from a road and communication information between cars, as described in xe2x80x9cITSxe2x80x9d edited by Asahi Shinbunsha and Asahi Original, published in 1998, pp. 42-47.
In the above described conventional signal control technique, traveling cars are controlled signals. In a road section other than signal intersections, control of traveling cars is difficult. For example, therefore, the traveling cars travel in a way remarkably different from hypothesis made when determining the offset of the signals. In this way, completely free traveling is possible. If cars conduct unnecessary acceleration and stop, therefore, smoothness and efficiency of the traffic flow are hampered. In addition, the hampered smoothness sometimes exerts bad influences upon the safety and environment.
Furthermore, in the conventional automatic driving control technique, the car control becomes difficult if there are automatically driven cars and ordinary cars are mixedly present on the same lane.
Therefore, an object of the present invention is to control traveling cars efficiently even on a simple road section other than signal intersections by setting probe cars which lead traveling cars and suitably controlling the probe cars.
Another object of the present invention is to provide a traffic control system for controlling car groups each having a probe car at the head thereof or the overall traffic flow including the car groups by suitably controlling the probe cars.
Still another object of the present invention is to conduct signal control so as not to divide a car group having a probe car at the head thereof by a red light.
Yet another object of the present invention is to provide such an operational form of a traffic control system that drivers of probe cars are supplied with an incentive according to the driver""s degree of contribution and persons participating in the benefits of the probe cars cast a burden according to the degree.
The above described objects are achieved by a probe car control method for controlling behavior of cars, including the steps of: inputting a control strategy concerning behavior of a probe car and/or a car group concerning behavior of a car group having a probe car at head thereof, on the basis of a road map database or traffic data collected in real time; evaluating propriety of the strategy; and transmitting a proper strategy to the probe car to control the probe car. Or the above described objects are achieved by a storage medium storing a program for executing the probe car control method.
The probe car control according to the present invention includes a road map database; a car group control strategy input section for inputting a control strategy concerning behavior of a probe car and/or a car group strategy concerning behavior of a car group having a probe car at head thereof, based on a road map database or traffic data collected in real time; a car group control strategy evaluating and determining section for evaluating propriety of the strategy and determining a proper strategy; and a car group control strategy transmission section for transmitting the proper strategy to the probe car.
As the control strategy of the probe car inputted by the car group control strategy input section, the following can be mentioned. The control strategy indicates an index concerning a speed such as a desired speed of the probe car and/or an index concerning steering operation such as a lane change. In a place where the driver lowers the traveling speed, such as a tunnel, a tollgate, a gate, fog, or road freezing, the control strategy is to set a desired speed before entering the place is lower than the current speed or a recommended speed of the place. In a place where the traveling speed is physically lowered, such as a sag or climbing section, the control strategy is to set a desired speed before entering the place is higher than the current speed or a recommended speed of the place. Or on a multilane road having two or more lanes for each way, the control strategy indicates that probe cars are disposed on all lanes and probe cars on respective lanes are made to travel in parallel.
In accordance with a different aspect of the probe car control apparatus, the car group strategy of the probe car inputted by the car group control strategy input section is forming car groups by disposing probe cars in suitable positions based on traffic data; canceling a car group by making a probe car leave a car group or making a probe car an ordinary car; or integrate car groups into one car group by controlling probe cars leading a plurality of car groups. In accordance with a different aspect of the probe car control apparatus, a method for disposing probe cars in the control strategy or car group strategy of probe cars inputted by the car group control strategy input section is: a method of selecting suitable cars as probe cars from among traveling ordinary cars, based on traffic data; or a method of previously disposing cars dedicated cars to be used as probe cars, selecting probe cars to be squeezed between ordinary cars, and selecting positions and methods of squeezing.
In accordance with a different aspect of the probe car control apparatus, subject cars of the control strategy or car group strategy of probe cars inputted by the car group control strategy input section are all cars traveling on a subject section.
In accordance with a different aspect of the probe car control apparatus, indices used in an evaluation function for evaluating propriety of the strategy in the car group control strategy evaluating and determining section includes: travel time (average speed), traffic jam length, a number of times of stop, and variation of speed (standard deviation), serving as indices concerning efficiency; the number of times of rapid deceleration occurrence, the number of times abnormal approach between cars, the number of times of crashes, and stability of a traffic flow at the time of following movement (local stability/asymptotic stability), serving as indices concerning safety; or exhaust volume of matters determined by the Environmental Pollution Prevention Act and the Air Pollution Control Act, such as hydrocarbon (HC), carbon monoxide (CO), nitrogen oxide (NOx), lead compounds, particulate matters, acoustic power level of road traffic noise, exhaust volume of carbon dioxide, fuel consumption, and road traffic vibration, serving as indices concerning environment.
A probe car control apparatus which achieves the above described objects may be a probe car control apparatus including a map database; a car group strategy input section for inputting signal indication schedule data so as not to divide a car group having a probe car at head thereof by a red light, based on the database or traffic data collected in real time; and a car group control strategy evaluating and determining section for evaluating propriety of the signal indication schedule data and determining proper signal indication schedule data.
In accordance with a different aspect of the probe car control apparatus, the car group control strategy evaluating and determining section includes a traffic simulator for evaluating propriety of the strategy.
In accordance with a different aspect of the probe car control apparatus, the traffic data includes: car traveling data transmitted from an in-vehicle terminal having a transmission function via radio communication means such as a beacon on a road or a base station of portable telephone or PHS; fixed point passing traffic data measured by a car sensor on a road; road image processing data measured by an image sensor; or indication schedule data of intersection signals.
In order to achieve the above described objects, in a traffic control system according to the present invention includes: a traffic data storage for collecting and storing traffic data in real time; the above described probe car control apparatus; and a radio communication section serving as intermediation means for coupling an in-vehicle terminal, the probe car control apparatus, and the traffic data storage, or an intersection signal by using radio communication, a car group having a probe car at head thereof or a whole traffic flow including the car group is controlled by controlling a probe car having the in-vehicle terminal.
In accordance with a different aspect of the traffic control system, there is provided such an operational form that some incentive is given to drivers of probe cars depending upon the degree of contribution, and persons who benefit from the probe cars bear the expense.
In order to achieve the above described objects, a traffic control system according to the present invention includes: a traffic data storage for collecting and storing traffic data in real time; and a probe car control apparatus according to claim 11; a signal control device for controlling indication of a signal; and a signal. A a car group having a probe car at head thereof or a whole traffic flow including the car group is controlled by controlling an intersection signal so as not to divide a car group having a probe car at head thereof by a red light.